Would I be able to still have the quadro 4000 in combination with the GTX 660ti? I need the quadro4k for work.

Your quadro 4000 has TDP of 142W and one 6-pin power connector. The GTX 660ti has two 6-pin connectors and TDP of 150W. As long as you don't buy any overclocked or supercharged version of 660ti, you could be fine within the 300W limit (75w x 2 from two auxiliary power ports and 75W x 2 from PCIe slot). However you need a special cable connector like this to deal with the extra 6-pin connector on the GTX 660ti and split one auxiliary power source between the two video cards (use another cable to the other 6-pin connector). Or you could get a GTX 660 which has only one 6-pin connector and 140W TDP, and save all the troubles.

If I remember correctly the GTX cards do not have an EFI, and hence will not work until th drivers are loaded, i.e. not work in the boot sequence screen. However, the Radeon HD7970 will, and it's almost as fast...